MongoDB is very good at storing data in JSON format. And Mongoose, a Node.js Object Document Mapper, makes it easy to work with the data stored in your Mongo DB database. An ODM, or object document mapper, simply put, translates between your objects in code and the document representation of the data. It creates an abstraction layer between the application code and the database and allows for easier programming. MongoDB is schema less, meaning each object stored in a collection does not need to have properties similar to other objects. This provides great flexibility for the developers to store heterogeneous pieces of data.